Senate Minority Leader Charles E. Schumer said Monday he’ll vote against a slate of President Trump’s Cabinet nominees, saying he feels compelled to send a signal of defiance to the new administration.

Mr. Schumer had already said he’d oppose nominees to lead the State, Education and Justice departments, and on Mondayhe added the picks for Treasury, Health and Human Services and Labor departments, as well as the White House budget director and the head of the Environmental Protection Agency.

Democrats have put up the fiercest resistance to a new president in modern times, delaying nearly all of Mr. Trump’s picks and forcing roll call votes on each of them. They’ve said their opposition is aimed both at the nominees themselves and at Mr. Trump, hoping to deny him the people they fear would enable his agenda.

“I will vote against nominees who will be the very worst of this anti-immigrant, anti-middle-class, billionaires’ club cabinet,” the New York Democrat said.

He said earlier Monday that he would also demand delays in action on the nominees until they say where they stand on Mr. Trump’s new executive order imposing a temporary ban on travel from seven terrorism-connected countries and a temporary halt to admitting new refugees.

Mr. Schumer did vote to confirm the picks that have cleared so far to lead the CIA, Homeland Security and the Defense Department. He also voted to confirm the new ambassador to the U.N.